<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
    .box {
      width: 66px;
      height: 66px;
      background-color: #ff2a58;
    }
  </style>
</head>
<body>
<div class="box">123</div>
<ul>
  <li>abc</li>
  <li>abc</li>
  <li>abc</li>
</ul>
<script>
  var ul = document.querySelector('ul');

  ul.addEventListener('click', function (e) {
    console.log(e.target);  // => <li>abc</li>
    console.log(this);      // => <ul><li>abc</li><li>abc</li><li>abc</li></ul>
  })
</script>
</body>
</html>